Abstract: The lithology of Cretaceous Xiagou Formation reservoir in Qingxi long term production block of Yumen Oilfield is particular:terrigenous elastic rock takes 35.16%,carbonate rock 33.84% and clay mineral 31.01%.The permeability is low,porosity is low,and the natural fractures are developed.The average depth of the middle reservoir is 4200 m,the average temperature is 120℃.For the particular lithologic reservoir,through analysis of slice appraisal,X-diffraction,scanning electron microscope and so on,combining them with the research results like acid etching diversion capacity simulation test,reservoir numeric simulation and optimized design,this paper presents a particular stimulation process-deep acid fracturing with friction reducing acid plus closed acidizing with multi-component acid.This paper also presents the liquid sys-tern suitable for reservoir reforming.Field application of this process in well Liu102 shows that the stimulation effect is obvious:oil is increased by 102 t per day,and the multiple of incremental oil recovery is 10.